I built this jig so I could make tenons with ease and cut both sides of the tenon in one path .
I use two inexpensive 7 1/4" blades (about $3.00 each ) and a MDF spacer that matches my arbor washers and some dado shims to set the blades to the proper distance apart for the thickness of the required tenon size .
The tenon is cut in one path through the saw blades and the outside waste is cut away using my sled with a stop block .
The tenon jig is a common straight forward design made from Baltic Birch ply and is guided on the saw fence and allows for easy adjusting and a handle well out of the way and allows for easy adjusting
The jig has to be absolutely square in all directions to the saw top to get perfect results when assembling the project .
The length of the tenon is easily set by using the previously cut dado as a height gage (see PIC )
The saw blade and spacer and shim stack is very affordable and easily stored as a set for the next project .